GMC Code P1391: CKP/CMP Synchronization Problem

(Intermittent Loss of CMP or CKP Signal)

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Technical Meaning

• Fault: The control module (PCM) detects an intermittent loss of synchronization between:
  • CKP (Crankshaft Position Sensor): Crankshaft position sensor.
  • CMP (Camshaft Position Sensor): Camshaft position sensor.
• Impact: Engine timing error → Desynchronization of injection and ignition → Risk of stalling, misfires, or hard starting.

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Affected GMC Models

Model	Common Engines	Years
GMC Sierra	4.3L V6, 5.3L/6.0L V8	1999-2019
GMC Yukon	5.3L/6.2L Vortec	2000-2020
GMC Canyon	2.8L/3.5L/3.7L I4/I5	2004-2012
GMC Acadia	3.6L V6 (LLT/LFX)	2007-2017
GMC Envoy	4.2L I6, 5.3L V8	2002-2009

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Common Symptoms

• ⚠️ Engine stalling at idle (especially when the air conditioning is active).
• 🔧 Hard starting (engine cranks for a long time before starting).
• ⚡ Misfires under acceleration or under load.
• 📈 Unstable idle (perceptible vibrations in the cabin).
• 💡 Check engine light on (sometimes accompanied by P0016 for desynchronization).

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Specific Causes in GMC

1. Electrical Problems (65-75% of cases):
   • Damaged CKP/CMP wiring due to heat from the exhaust manifold (common on Sierra/Yukon).
   • Oxidized connectors (moisture/road salt, especially on Canyon/Acadia).
   • Blown fuse (check the under-hood fuse box: *PCM Fuse 10A/15A*).
2. Mechanical Failures:
   • Cracked or rusty crankshaft reluctor wheel (exposed Vortec V8 engines).
   • Stretched timing chain (progressive symptom on high-mileage engines).
   • Metal debris stuck to the CKP sensor (magnetism from wear particles).
3. Other Causes:
   • Oil leaks submerging the CMP sensor (aging seals on Envoy I6).
   • Failing PCM (rare, but documented on Acadia 2007-2010).

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Cost Analysis: The estimated cost of repairs related to GMC Code P1391 can vary significantly. Depending on the severity of the problem, costs can range from simple sensor replacements to more complex repairs, such as timing chains. It is advisable to get multiple quotes to ensure quality service at a reasonable price.

Step-by-Step Diagnosis

1. Advanced OBD2 Scan:
   • Check for related codes (P0335 = CKP, P0340 = CMP, P0016 = desynchronization).
   • Observe live data: CKP:CMP Ratio must be 2:1 (2 crankshaft revolutions = 1 camshaft revolution).
2. Physical Inspection:
   • Sensor locations:
     CKP: On the engine block, near the flywheel (access from underneath).
     CMP: On the cylinder head, timing side (often hidden under intake manifolds).
   • Critical points:
     • Wires rubbing against the exhaust manifold (Sierra 5.3L).
     • CMP connector flooded with oil (Yukon 6.0L).
3. Electrical Tests:
   

   Sensor	Voltage (V)	Resistance (Ω)
   CKP	5V or 12V	500–1,500
   CMP	5V	200–1,000

   🔍 Measure off-circuit with a multimeter.

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Recommended Repairs

Solution	Estimated Cost (USD)	Urgency
Replace CMP sensor	$60–120	🔧🔧
Repair CKP harness	$80–200	🔧🔧
Clean CKP reluctor wheel	$0 (DIY)	🔧
Replace timing chain	$800–1,500	⚠️⚠️
Reprogram PCM	$150–300	⚠️

Typical GMC Case: On the Sierra 5.3L Vortec, the CKP harness runs near the exhaust manifold → Melted insulation = short circuit. Solution: Replace harness + heat shield.

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Mistakes to Absolutely Avoid

• 🚫 Ignoring the timing chain: A stretched chain is a recurring cause on engines >150,000 km.
• 🚫 Forgetting to check fuses: A blown PCM fuse mimics a sensor fault.
• 🚫 Neglecting CMP seal: A leaking seal floods the sensor → Recurring failure.

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Specific GMC Technical Tips

1. Diagnostic Tools: Use a Tech2 or MDI scanner (official GM tools) to access advanced PCM parameters.
2. Relearning Procedure: After replacing a sensor, perform a “Crank Position Sensor Variation Learn” via the scanner.
3. Emergency Solution: If the engine stalls, restart it immediately – the PCM attempts an automatic resynchronization.

⚠️ Safety Warning:

• A P1391 code + severe misfires can damage the catalytic converter (overheating).
• If the check engine light flashes, stop the vehicle → Risk of catalytic converter destruction.

*Source: GMC Service Manual, technical service bulletins TSB 18-NA-355 (2018).*

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ℹ️ Note: On Ecotec 3.6L engines (Acadia/Terrain), the P1391 code is often related to a faulty PCM control relay – check the under-hood relay box before any sensor replacement.

Additional Explanation: Understanding OBD II trouble codes is essential for diagnosing engine problems. When encountering a code like GMC Code P1391, it is imperative to examine other engine-related systems, as a failure in one component can often cause errors in others. For example, a crankshaft position sensor failure can affect the ignition system, leading to decreased performance.

Case Study: Consider a GMC Yukon owner who reported hard starting. After diagnosis, the GMC Code P1391 was found. By replacing the CMP sensor and checking the connections, the problem was resolved. This case illustrates the importance of a complete diagnosis before undertaking costly repairs.

Recommended Practices: To avoid future problems related to GMC Code P1391, it is advisable to perform regular vehicle inspections, particularly of cables and sensors. Preventive maintenance can reduce the risk of failure and improve your engine’s longevity.

Owner Testimonials: Many GMC owners who encountered GMC Code P1391 report significant improvements after proper repairs. These testimonials highlight the importance of prompt and appropriate interventions to avoid long-term damage, such as that caused to a catalytic converter.

Driver Education: Drivers should be familiar with the warning signals their vehicle may emit. A check engine light or unusual noise can be an indicator that something is wrong. By knowing the symptoms related to GMC Code P1391, owners can act quickly to avoid more costly repairs.

(Intermittent Loss of CMP or CKP Signal)

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Technical Meaning

• Fault: The PCM detects an intermittent loss of synchronization between the crankshaft position sensor (CKP) and the camshaft position sensor (CMP).
• Impact: Ignition and injection desynchronization → Risk of stalling, misfires, or failure to start.
• Honda Specificity: On i-VTEC engines, this code may disable the variable camshaft system, reducing power and fuel economy.

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Affected Honda Models

Model	Common Engines	Years
Honda Civic	1.6L, 1.7L, 2.0L (D-Series, R-Series)	2001-2015
Honda Accord	2.4L K24, 3.0L/3.5L V6 (J-Series)	2003-2017
Honda CR-V	2.0L/2.4L (K-Series)	2002-2016
Honda Odyssey	3.5L J35 V6	2005-2020
Honda Pilot	3.5L J35 V6	2006-2015

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Common Symptoms

• ⚠️ Sudden stalling at idle (especially with air conditioning activated).
• 🔧 Extended cranking (engine turns for 5-10 seconds before starting).
• ⚡ Misfires during acceleration (feeling of hiccups).
• 📉 Loss of power (i-VTEC disabled as a safety measure).
• 💡 Check engine light on + VSA light sometimes activated.

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Specific Causes in Hondas

1. Electrical Problems (60-70% of cases):
   • CKP wires chewed by the fan (especially on Civic/CR-V).
   • Oxidized CMP connector (low location, exposed to water/snow).
   • Blown fuse (check the fuse box under the steering wheel: PCM 15A Fuse).
2. Mechanical Failures:
   • Damaged CKP reluctor wheel (bent or rusty teeth, common on Civic).
   • Stretched timing chain (high-mileage K24/J35 engines >150,000 km).
   • Metal debris on CKP sensor (engine or transmission wear).
3. Other Causes:
   • CMP valve cover gasket leak (oil floods the sensor on Accord/CR-V).
   • Faulty main relay (PGM-FI, blocks sensor power supply).

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Step-by-Step Diagnosis

1. Honda-Specific OBD2 Scan:
   • Use an HDS (Honda Diagnostic System) scanner to read related codes:
     • P0335 (CKP), P0340 (CMP), P2646 (VTEC problem).
   • Check the “CMP Pattern” in live data: it should be stable.
2. Physical Inspection:
   • Sensor locations:
     CKP: Behind the engine pulley (transmission side).
     CMP: On the cylinder head, under the valve cover (Accord) or near the pulley (Civic).
   • Critical points:
     • CKP wires rubbing against the fan (Civic).
     • Oil leak at CMP gasket (CR-V/Accord).
3. Electrical Tests:SensorVoltage (V)Resistance (Ω)CKP5V or 12V350–700 ΩCMP5V250–1,000 Ωℹ️ Disconnect the connector to measure.

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Recommended Repairs

Solution	Estimated Cost (USD)	Urgency
Replace CMP sensor	$50–120	🔧🔧
Repair CKP harness	$70–180	🔧🔧
Clean CKP reluctor wheel	$0 (DIY)	🔧
Replace CMP gasket	$30–90	🔧
Adjust/replace timing chain	$600–1,200	⚠️⚠️

Concrete example: On a Honda Civic 1.7L, the CKP harness passes near the fan → Wires severed. Solution: Replace the harness + add protective sleeving.

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Mistakes to Absolutely Avoid

• 🚫 Ignoring the timing chain: A stretched chain is common on K24s (Accord/CR-V) and triggers P1391 + P0016.
• 🚫 Forgetting the PGM-FI relay: Test it before replacing a sensor (under the dashboard on the driver’s side).
• 🚫 Neglecting sealing gaskets: An oil leak quickly destroys the new CMP sensor.

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Honda-Specific Technical Tips

1. Diagnostic Tools:
   • HDS scanner mandatory for CKP relearn after replacement (“CKP Pattern Clear” procedure).
   • Economical alternative: Launch or Autel scanner compatible with Honda.
2. Emergency Procedure:
   • If the engine stalls: Turn the ignition off for 10 seconds → Restart (the PCM attempts a resynchronization).
3. Quick Check:
   • Test the main relay (PGM-FI): Listen for a click when turning the ignition on, or measure 12V at the CMP/CKP connector.

⚠️ Safety Warning:

• An untreated P1391 can cause a complete breakdown (engine no longer starts).
• If the VSA light comes on, check the stability control system (disabled as a safety measure).

*Source: Honda Workshop Manual (HDS), technical service bulletin TSB 12-045 (2012) for recurring issues on CR-V 2010-2014.*

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ℹ️ Note: On J35 V6 engines (Odyssey/Pilot), code P1391 is often related to a faulty VTEC solenoid → Check it before replacing the CMP!

Meaning of Code P1391

The Isuzu P1391 code on Isuzu vehicles indicates a problem in the camshaft position sensor (CMP) circuit. This sensor plays a crucial role in synchronizing the fuel injection system and ignition.

Severity of the Problem

• Moderate to High: This fault can cause:
  • ⚠️ Starting problems
  • 🚗 Poor engine performance
  • ⛽ Increased fuel consumption
  • 🌫️ Increased pollutant emissions

Common Symptoms

• 🚗 Engine idling irregularly
• ⚡ Loss of power during acceleration
• ⚠️ Check engine light on
• 🔥 Occasional misfires
• 🔋 Cold weather starting problems

Possible Causes

1. Electrical problems:
   • Faulty CMP sensor
   • Damaged wiring or corroded connectors
   • Short circuit or open circuit in the harness
2. Mechanical problems:
   • Damaged camshaft gear wheel
   • Misaligned timing
3. Other causes:
   • Power supply or grounding issue
   • Engine Control Module (ECM) failure

Diagnostic Procedure

Step 1: Visual Inspection

• 🔍 Locate the CMP sensor (usually near the camshaft pulley)
• 🔌 Check the condition of the connector and wiring
• � Look for signs of damage or corrosion

Step 2: Electrical Tests

• 🔋 Check the sensor’s power supply (5V) and ground
• 📏 Measure the sensor’s resistance (compare to specifications)
• ⚡ Test the output signal with an oscilloscope

Step 3: Mechanical Check

• ⚙️ Inspect the gear wheel for missing or damaged teeth
• 🔧 Check the timing alignment

Step 4: Advanced Diagnostics

• 💻 Use an OBD-II scanner to:
  • Read live sensor data
  • Check for associated codes
  • Analyze the CMP signal graph

Common Repairs

• 🔧 Replace the faulty CMP sensor
• 🔌 Repair or replace damaged wiring
• ⚙️ Correct the timing alignment if necessary
• 💻 Update the ECM software if required

Prevention Tips

• 🛠️ Replace the CMP sensor as part of preventive maintenance
• 🔍 Regularly inspect wiring and connectors
• ⛽ Use quality OEM parts

Average Repair Cost

• CMP sensor: €50-€150
• Labor: €50-€150
• *Estimated total: €100-€300*

Conclusion

The P1391 code on Isuzu requires immediate attention to avoid potential engine damage. Accurate diagnosis will identify the exact cause and allow for appropriate repairs.

🔧 Professional tip: If you are not familiar with electrical diagnostics, consult a qualified mechanic specialized in Isuzu vehicles.

🚗 Is your Isuzu displaying this code? Share your experience in the comments to help other owners!

Technical Meaning

The Jeep P1391 code on Jeep vehicles indicates a desynchronization between the camshaft position sensor (CMP) and crankshaft position sensor (CKP) signals. This fault disrupts engine management by affecting:

• ⏱️ Injection timing
• 🔥 Ignition control
• ⚙️ Valve timing

Severity and Consequences

Level	Impact
Moderate	Unstable idle, power loss
High	Risk of stalling, catalytic damage

Characteristic Symptoms

• 🚗 Hard starting (especially when cold)
• ⚡ Random misfires
• ⛽ Excessive fuel consumption up to 20%
• 🌡️ Abnormal overheating
• ⚠️ Check Engine light on + limp mode

Probable Causes Tree

Diagram

Advanced Diagnostic Procedure

1. Electrical Check (Tools: Multimeter, Oscilloscope)

• CMP resistance test: 200-1000Ω (refer to manual)
• CKP/CMP signal: Check pulse alternation
• Sensor power supply: 5V ±0.5V

2. Mechanical Check

• 🔧 Chain tension: Max 5mm play
• ⚙️ Timing mark alignment
• 🔍 Sprocket inspection (broken teeth)

3. ECM Diagnosis

• 💻 Software update
• 🔋 ECU power test (stable 12V)

Specific Jeep Cases

• Wrangler JK 3.8L: Recurrent CMP connector issue exposed to elements
• Grand Cherokee 4.7L: Premature chain tensioner wear
• Renegade 1.4T: Sensitivity to voltage variations

Average Repair Costs

Intervention	Parts Cost	Labor
CMP replacement	80-150€	0.5h
Chain replacement	300-600€	4-6h
ECM reprogramming	100-200€	1h

Technical Tips

1. Priority: Always check wiring first before condemning a sensor
2. Tip: Use an oscilloscope to compare CMP/CKP signals
3. Prevention: Replace chain every 150,000km on Pentastar engines

Common Mistakes

• 🔌 Neglecting sensor connector (frequent corrosion)
• ⏳ Forgetting to reset ECM adaptation after repair
• 🔄 Confusing with ignition coil problem

Important note: On recent Jeeps (after 2015), this code may require mandatory software update before any other intervention.

Technical Meaning

The Mitsubishi P1391 code on Mitsubishi vehicles indicates a fault in synchronization between the camshaft position sensor (CMP) and crankshaft position sensor (CKP) signals. This issue primarily affects:

• 🕒 Injection timing
• ⚡ Ignition control
• 🔧 Variable valve timing management (MIVEC on certain models)

Severity and Consequences

Level	Impact
Moderate	Unstable idle, slight power loss
High	Risk of stalling, catalyst damage

Mitsubishi-Specific Symptoms

• 🚗 Hard starting (especially on Lancer and Outlander)
• ⚠️ Check Engine light flashing + “Limp Home” mode
• ⛽ Noticeable increase in fuel consumption
• 🔊 Metallic knocking (if timing belt issue)

Model-Specific Causes

For 4G6 engines (Lancer EVO)

• Faulty CMP sensor (common issue)
• Premature timing belt wear
• Hydraulic tensioner problem

For 6B3 engines (Outlander)

• Connector corrosion (low sensor position)
• Excessive timing chain play
• MIVEC variable phasing failure

For 4N1 engines (recent ASX)

• Sensitivity to voltage variations
• ECM software update required

Diagnostic Procedure

Step 1: Electrical Check

1. Sensor testing:
   • CMP resistance: 400-800Ω (at 20°C)
   • CKP signal: Check for clean square wave
2. Wiring check:
   • Measure continuity between ECM and sensors
   • Verify no short circuit to ground

Step 2: Mechanical Check

• 🔍 Timing mark alignment
• ⚙️ Belt/chain tension (5-6mm max deflection)
• 🔧 Condition of sprockets and guides (abnormal wear)

Step 3: ECM Diagnosis

• 💻 Live data reading:
  • Real-time CMP/CKP comparison
  • Calculated phase shift verification
• 🔄 Software update (often required on Pajero IV)

Recommended Solutions

For Common Models

1. CMP sensor replacement (part # MD614602 for Lancer)
2. Connector cleaning + dielectric grease application
3. Timing adjustment with Mitsubishi special tools

For Recurring Problems

• Complete timing kit (including hydraulic tensioner)
• ECM reprogramming (update TSB 18-46-003)

Average Repair Costs

Intervention	Parts Cost	Labor
CMP Sensor	90-180€	0.8h
Timing Belt	120-250€	3.5h
Reprogramming	80-150€	1h

Specific Technical Tips

1. Always use OEM parts for sensors
2. Systematically check phasing after intervention
3. On Outlander PHEV: Disconnect HV power before diagnosis

Common Mistake: Neglecting water pump inspection during timing belt replacement (causing subsequent overheating)

⚠️ Warning: On Mitsubishi Diesel (4N1), this code may mask a rail pressure sensor problem. Always check associated codes.

Meaning of Saab P1391 Code

The P1391 code on a Saab is generally related to a problem with the Camshaft Position Monitor (CMP) system. It may indicate misalignment between the crankshaft and camshaft, or a malfunction of the camshaft position sensor (CMP).

Possible Causes

1. Timing Issue: The timing belt may be misaligned or worn.
2. Faulty CMP Sensor: The camshaft position sensor may be damaged or dirty.
3. Electrical Problem: Damaged wires, corroded connectors, or short circuit.
4. Timing Adjuster Issue (if applicable).
5. Engine Control Unit (ECU) Problem – Rare, but possible.

Diagnosis and Solutions

1. Check the Timing Belt:
   • Inspect alignment and tension.
   • If worn or jumped, replace it.
2. Test the CMP Sensor:
   • Check resistance and signal with a multimeter.
   • Clean or replace the sensor if necessary.
3. Inspect the Wiring:
   • Look for broken wires or corroded connectors.
4. Reset the Fault:
   • Clear the code with an OBD2 tool and see if it returns.
5. Check the ECU:
   • If the problem persists, reprogramming or replacing the ECU may be necessary.

Conclusion

The P1391 code on a Saab is often related to a timing issue or CMP sensor problem. A thorough inspection of the timing system and electrical components is required to resolve the issue.

The Suzuki P1391 code on a Suzuki vehicle is typically related to a problem with the synchronization between the crankshaft and the camshaft or a malfunction of the camshaft position sensor (CMP). This fault can affect engine performance and illuminate the check engine light (CEL).

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1. Meaning of Code P1391

The P1391 code means:

• “Correlation Error Between the Crankshaft Position Sensor (CKP) and the Camshaft Position Sensor (CMP)”
• The engine control unit (ECU) detects an abnormal discrepancy between the signals from the two sensors.

Affected Suzuki Models (among others):

• Suzuki Swift
• Suzuki Grand Vitara
• Suzuki SX4
• Suzuki Baleno

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2. Possible Causes of P1391

A. Mechanical Problems

• Misaligned timing belt (off by one or more notches)
• Stretched or worn timing chain (if the engine is equipped with one)
• Problem with the tensioner or timing pulleys

B. Electrical/Sensor Problems

• Faulty camshaft position sensor (CMP)
• Defective crankshaft position sensor (CKP)
• Damaged/corroded wires or connectors

C. Other Possible Causes

• Engine oil problem (insufficient pressure affecting the timing actuator)
• Problem with the variable valve timing (VVT) actuator (if the engine is equipped with one)
• ECU failure (rare)

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3. Diagnosis and Solutions

Step 1: Check the Timing Belt/Chain

• Check the alignment of the marks (crankshaft and camshaft).
• If the belt/chain is worn or misaligned, replace it and correctly realign the timing.

Step 2: Test the CKP and CMP Sensors

• Disconnect and measure the resistance with a multimeter (check the manual specifications).
• Clean the sensors (sometimes dirt can interfere with the signal).
• Replace the faulty sensor if necessary.

Step 3: Inspect the Wiring and Connectors

• Check for cut, chafed, or corroded wires.
• Clean the connectors with electrical contact cleaner spray.

Step 4: Check the Engine Oil and VVT Actuator

• Check the oil level and quality (oil that is too old can clog the VVT system).
• If the engine has a VVT system, check its operation.

Step 5: Reset the Fault and Test

• Clear the code with an OBD2 tool and see if it returns after a road test.
• If the code reappears, check the ECU (rare but possible failure).

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4. Conclusion

The P1391 code on Suzuki typically indicates a engine timing problem (timing system or sensors).

• Priority 1: Check the timing belt/chain.
• Priority 2: Test the CKP/CMP sensors and their wiring.

If the problem persists after these checks, a more in-depth analysis with an advanced scanner may be necessary.

The Volkswagen P1391 code on a Volkswagen (Golf, Passat, Polo, Tiguan, etc.) generally indicates a problem with the correlation between the crankshaft position sensor (CKP) and the camshaft position sensor (CMP). This fault can lead to rough idling, loss of power, or even the engine entering a limp mode.

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1. Meaning of the P1391 code on Volkswagen

The P1391 code means:

• “Disagreement between the crankshaft position sensor (CKP) and camshaft position sensor (CMP) signals”
• The ECU detects that the two sensors are not synchronized as expected.

Affected Volkswagen models (among others):

• VW Golf (4, 5, 6, 7)
• VW Passat (B5, B6, B7)
• VW Polo (9N, 6R, 6C)
• VW Tiguan (1G, 2G)
• VW Jetta, Touran, Scirocco

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2. Possible causes of P1391 on Volkswagen

A. Mechanical problems

• Incorrectly timed timing belt (off by one or more teeth)
• Stretched timing chain or faulty tensioner (on chain-driven engines, like the 1.4 TSI or 2.0 TDI)
• Problem with the tensioner pulley or worn chain guide

B. Sensor failure

• Faulty camshaft position sensor (CMP)
• Defective crankshaft position sensor (CKP)
• Dirty or damaged sensor (oil, debris)

C. Electrical problems

• Cut wires, oxidized connectors, or short circuits
• Poor sensor supply voltage

D. Other possible causes

• Problem with the variable valve timing (VVT) actuator if present
• Insufficient or poor-quality engine oil (affects VVT)
• ECU failure (rare but possible)

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3. Diagnosis and solutions

Step 1: Check the timing belt/chain

• Check the alignment of the timing marks (crankshaft and camshaft).
• If the belt/chain is misaligned, worn, or loose, replace and recalibrate it.
• On chain-driven engines (e.g., 1.4 TSI, 2.0 TDI), check the condition of the chain and tensioner.

Step 2: Test the CKP and CMP sensors

• Use a multimeter to check the resistance (reference: technical manual).
• Clean the sensors (often soiled by oil).
• Replace the faulty sensor if necessary.

Step 3: Inspect the wiring and connectors

• Check for broken or oxidized wires between the sensors and the ECU.
• Clean the connectors with contact spray.

Step 4: Check the variable valve timing (VVT) and engine oil

• Check the oil level and quality (oil that is too old can block the VVT).
• If the engine has a VVT system, check its proper operation.

Step 5: Reset the fault and test

• Clear the code with VCDS (VAG-COM) or an OBD2 tool.
• Perform a road test to see if the code returns.
• If the problem persists, check the ECU (in-depth diagnosis required).

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4. Conclusion

The P1391 code on Volkswagen is often related to:
✅ A timing issue (timing belt/chain) → Check the belt/chain.
✅ A faulty CMP or CKP sensor → Test and replace if necessary.
✅ An electrical problem (wires, connectors) → Inspect the wiring.

The default code P1392 is a generic OBD-II code related to a problem with synchronization between the crankshaft and camshaft, similar to P1391 but with specificities depending on the manufacturer. It can affect engine performance and trigger the “Check Engine” light.

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1. Meaning of Code P1392

The code P1392 generally means:

• “Error in correlation between the crankshaft position sensor (CKP) and the camshaft position sensor (CMP)”
• “Engine timing or synchronization problem”

Difference between P1391 and P1392:

• P1391 → Slight desynchronization (e.g., off by one tooth).
• P1392 → More significant desynchronization (e.g., multiple teeth off or serious mechanical issue).

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2. Possible Causes of P1392

A. Mechanical Problems (most common)

🔧 Misaligned timing belt/chain (misalignment, slippage, wear)
🔧 Faulty chain tensioner or guide (chain engines)
🔧 Stuck or faulty variable valve timing (VVT) actuator

B. Sensor Failures

📡 Faulty camshaft position sensor (CMP)
📡 Defective crankshaft position sensor (CKP)
📡 Dirty or damaged sensors

C. Electrical Problems

🔌 Cut wires, oxidized connectors, or short circuits
🔌 Sensor power supply issue

D. Other Causes

🛢️ Insufficient or poor-quality engine oil (affects VVT)
💻 ECU failure (rare)

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3. Diagnosis and Solutions

Step 1: Check the Timing Belt/Chain

• Check alignment marks (crankshaft and camshaft).
• If the belt/chain is misaligned or worn, replace and recalibrate it.
• On chain engines (e.g., VW 1.4 TSI, BMW N20): check for stretching and the tensioner.

Step 2: Test the CKP and CMP Sensors

• Measure resistance with a multimeter (specific values per model).
• Clean or replace faulty sensors.

Step 3: Inspect Wiring and Connectors

• Check for broken or oxidized wires.
• Clean connectors with contact spray.

Step 4: Check the VVT Actuator and Engine Oil

• Check oil level and quality (old oil can block VVT).
• If the VVT is faulty, replace it.

Step 5: Reset and Test

• Clear the code with an OBD2 tool.
• Perform a road test to see if the code returns.

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4. Affected Manufacturers (examples)

• Volkswagen/Audi/Seat/Skoda: Timing or sensor issues.
• BMW/Mini: Stretched timing chain (e.g., N47/N63 engines).
• Toyota/Lexus: Faulty VVT-i actuator.
• Honda: Timing or CMP sensor problem.

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5. Conclusion

The code P1392 generally indicates:
✅ A timing issue (timing system) → Check belt/chain.
✅ A faulty CMP/CKP sensor → Test and replace.
✅ An electrical or VVT problem → Inspect wiring and oil.

⚠️ If the problem persists after checking, professional diagnosis with an oscilloscope may be necessary.

Acura Fault Code P1392 – Complete Diagnostic

(Applicable to Acura/Honda models: TL, MDX, RSX, Integra, etc.)

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1. Specific Meaning for Acura

Code P1392 on Acura indicates:
“Problem with correlation between CKP (crankshaft) and CMP (camshaft) sensors – Intermittent Circuit”

➡️ This code is often associated with:

• Temporary or permanent desynchronization between the two sensors
• An intermittent electrical issue (more common than with P1391)
• Early wear of the timing chain (on some engines)

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2. Priority Causes for Acura

(Ranked in order of probability)

A. Electrical Problems (60% of cases)

• 📍 Loose or corroded CMP sensor connector (typical on 2000s Acura models)
• 📍 Rubbing of the wiring harness (especially on MDX 2001-2006)
• 📍 CMP sensor starting to weaken

B. Mechanical Problems (30% of cases)

• ⚙️ Excessive timing chain play (J-series V6 engines)
• ⚙️ Worn timing chain tensioner
• ⚙️ VTEC actuator problem

C. Other Causes (10%)

• 🔋 Poor power supply voltage (check alternator)
• 💻 ECU software issue (requires flash)

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3. Step-by-Step Acura-Specific Diagnostic

Step 1 – Quick Check

1. Disconnect/reconnect the CMP connector (often under the engine cover)
2. Clean contacts with WD-40 Contact Cleaner
3. Perform a road test

If the code returns →

Step 2 – Advanced Tests

Test	Method	Correct Values
CMP Resistance	Multimeter on terminals 1-2	350-700 Ω (depending on model)
CMP Signal	Oscilloscope preferred	Regular square signal
Power Supply	Measure voltage on + wire	12V with ignition on

Step 3 – Mechanical Check

1. Remove timing chain inspection plug (if present)
2. Check chain tension with Honda HDS diagnostic tool
3. Inspect hydraulic tensioner condition

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4. Most Common Solutions

• On RSX/Integra Type-S: Replace CMP sensor gasket (frequent oil leak)
• On MDX/TL 3.2L/3.5L: Tighten ECU connectors + preventive tensioner replacement
• On VTEC models: Complete oil change + synthetic 5W-30 oil

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5. Mistakes to Avoid

❌ Do not confuse with P0341 (CMP circuit problem)
❌ Do not ignore the code – can lead to serious misfire issues
❌ Avoid aftermarket sensors – prefer Denso or OEM

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6. Most Affected Acura Models

• MDX 2001-2006 (3.5L V6) – Connector issues
• RSX 2002-2006 – Oil leak on CMP
• TL 1999-2003 (3.2L) – Timing chain tensioner wear

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Average repair cost:

• $50-200 for simple electrical issue
• $400-800 for chain/tensioner replacement